|Publication number||US7876881 B2|
|Application number||US 11/901,485|
|Publication date||Jan 25, 2011|
|Filing date||Sep 17, 2007|
|Priority date||Sep 17, 2007|
|Also published as||CN101801272A, EP2197351A1, US20090074134, WO2009038613A1|
|Publication number||11901485, 901485, US 7876881 B2, US 7876881B2, US-B2-7876881, US7876881 B2, US7876881B2|
|Original Assignee||Siemens Medical Solutions Usa, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Non-Patent Citations (3), Referenced by (5), Classifications (16), Legal Events (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The embodiments described below relate generally to radiation treatment, and more particularly to imaging systems used in conjunction with such treatment.
According to conventional radiation treatment, a beam of treatment radiation is directed toward a tumor located within a patient. The radiation beam delivers a predetermined dose of therapeutic radiation to the tumor according to an established treatment plan. The delivered radiation kills cells of the tumor by causing ionizations within the cells.
Treatment plans are therefore designed to maximize radiation delivered to a target while minimizing radiation delivered to healthy tissue. However, a treatment plan is designed assuming that relevant portions of a patient will be in a particular position relative to a treatment device during treatment. If the relevant portions are not positioned exactly as required by the treatment plan, the goals of maximizing target radiation and minimizing healthy tissue radiation may not be achieved. More specifically, errors in positioning the patient can cause the delivery of low radiation doses to tumors and high radiation doses to sensitive healthy tissue. The potential for misdelivery increases with increased positioning errors.
Due to the foregoing, treatment plans are designed under the assumption that positioning errors may occur that may result in misdelivery of radiation. Treatment plans compensate for this potential misdelivery by specifying lower doses or smaller beam shapes (e.g., beams that do not radiate edges of a tumor) than would be specified if misdelivery was not expected. Such compensation may decrease as margins of error in patient positioning decrease.
It would therefore be beneficial to provide a system and method that may increase the accuracy of patient positioning during radiation treatment. When used in conjunction with conventionally-designed treatments, more accurate positioning may reduce chances of harming healthy tissue. More accurate patient positioning may also allow the use of more aggressive treatments. Specifically, if a margin of error in patient positioning is known to be small, treatment may be designed to safely radiate a greater portion of a tumor with higher doses than in scenarios where the margin of error is larger.
To address at least the above problems, some embodiments provide a system, method, medium, apparatus, and means to emit a megavoltage radiation beam from a treatment head toward a volume, emit a respective kilovoltage radiation beam from each of a plurality of X-ray sources toward the volume while the plurality of X-ray sources are substantially stationary with respect to the volume, receive the plurality of kilovoltage radiation beams at a detector after having passed through the volume, and generate a three-dimensional image of the volume based only on the plurality of kilovoltage radiation beams received by the detector while the plurality of X-ray sources were substantially stationary with respect to the volume. According to some embodiments, emission of the megavoltage radiation beam, emission of the respective kilovoltage radiation beam from each of the plurality of X-ray sources, and reception of the plurality of kilovoltage radiation beams occur simultaneously during a period at which the treatment head, the plurality of X-ray sources, and the detector are stationary.
According to some embodiments, provided are an apparatus including a treatment head to emit a megavoltage radiation beam toward a volume, a plurality of X-ray sources, each of the plurality of X-ray sources to emit a respective kilovoltage radiation beam toward the volume while the plurality of X-ray sources are substantially stationary with respect to the volume, a detector to receive the plurality of kilovoltage radiation beams after having passed through the volume, and a processor to generate a three-dimensional image of the volume based only on the plurality of kilovoltage radiation beams received by the detector while the plurality of X-ray sources were substantially stationary with respect to the volume.
In further aspects, a rotatable gantry is coupled to the treatment head and a housing houses the plurality of X-ray sources and the detector, wherein the housing is coupled to the gantry for rotation therewith. The housing may define an opening through which a portion of the treatment head passes when the housing is moved to a deployed position, and the detector and the plurality of X-ray sources may be fixed with respect to the treatment head in the deployed position.
Some embodiments provide an apparatus including a rotatable gantry, a treatment head coupled to the gantry, the treatment head to emit megavoltage radiation, and a housing coupled to the gantry, the housing to house a plurality of X-ray sources and a detector, wherein the housing defines an opening to pass a portion of the treatment head. According to further aspects, a device is coupled to the housing and to the gantry to move the housing toward the gantry to a parked position and to move the housing away from the gantry to a deployed position. A portion of the treatment head passes through the opening when the housing is moved to the deployed position. In some aspects, the detector and the plurality of X-ray sources are fixed with respect to the treatment head in the deployed position.
The claims are not limited to the disclosed embodiments, however, as those skilled in the art can readily adapt the teachings herein to create other embodiments and applications.
The construction and usage of embodiments will become readily apparent from consideration of the following specification as illustrated in the accompanying drawings, in which like reference numerals designate like parts, and wherein:
The following description is provided to enable a person in the art to make and use some embodiments and sets forth the best mode contemplated by the inventor for carrying out some embodiments. Various modifications, however, will remain readily apparent to those in the art.
Linac 10 generates and emits the radiation, and is primarily composed of treatment head 11 and gantry 12. Treatment head 11 includes a beam-emitting device (not shown) for emitting a radiation beam used during calibration, verification, and/or treatment. The radiation beam may comprise electron, photon or any other type of radiation. According to some embodiments, the treatment radiation comprises megavoltage radiation. Also included within treatment head 11 is a beam-shielding device, or collimator (not shown) for shaping the beam and for shielding sensitive surfaces from the beam.
Accessory tray 13 may be mounted on treatment head 11 and may be configured to receive and securely hold attachments used during the course of treatment planning and treatment. These attachments may include reticles, wedges, or the like for further defining field sizes and intensities.
Treatment head 11 is coupled to a projection of gantry 12. Gantry 12 is rotatable around gantry axis 14 before, during and after radiation treatment. Although clockwise rotation is indicated by arrow 15, gantry 12 may also or alternatively rotate counter-clockwise according to some embodiments. Rotation of gantry 12 serves to rotate treatment head 11 around axis 14.
During radiation treatment, treatment radiation is delivered from linac 10 to the beam-emitting device of treatment head 11 and is emitted therefrom as a divergent beam. The beam is emitted towards an isocenter of linac 10. The isocenter is located at the intersection of an axis of the beam and gantry axis 14. Due to divergence of the radiation beam and the shaping of the beam by the aforementioned beam-shaping devices, the beam may deliver radiation to a volume of beam object 50 rather than only to the isocenter.
Table 40 supports beam object 50 during radiation treatment. Table 40 may be adjustable to assist in positioning a treatment area of beam object 50 at the isocenter of linac 10. Table 40 may also be used to support devices used for calibration and/or verification.
Imaging system 20 may be used to acquire images that may be used before, during and/or after radiation treatment. For example, imaging system 20 may be used to acquire images for verification and recordation of a target volume position and of an internal patient portal to which radiation is delivered. As will be described in detail below, imaging device 20 may provide three-dimensional images of a target volume during emission of a megavoltage radiation beam from treatment head 11. The three-dimensional images may be used to determine whether or not radiation treatment (i.e., emission of the radiation beam) should continue. Images acquired by imaging device 20 may be used to provide four-dimensional fluoroscopy of radiation treatment according to some embodiments.
Imaging system 20 comprises housing 21 including a plurality of x-ray sources (not shown) and a detector (not shown). Each of the plurality of X-ray sources may emit a respective kilovoltage radiation beam toward the target volume while the plurality of X-ray sources are substantially stationary with respect to the volume, and the detector is to receive the plurality of kilovoltage radiation beams after having passed through the target volume. In some embodiments, a three-dimensional image of the volume may be generated based on the plurality of kilovoltage radiation beams received by the detector. Due to the foregoing arrangement, the three-dimensional image may be generated based only on the plurality of kilovoltage radiation beams received by the detector while the plurality of X-ray sources were substantially stationary with respect to the volume. Some embodiments of housing 21 including a plurality of x-ray sources and a detector will be described in detail below.
Housing 21 defines opening 22 to pass a portion of treatment head 11. Opening 22 is 1100 to 1150 mm wide in some embodiments. Opening 22 may allow an interior diameter of imaging device 20 to be larger than would be possible in the absence of opening 22. According to some embodiments, housing 21 includes several fixed components, which may also allow for a larger interior diameter because other imaging elements may be located exterior to housing 21. The larger interior diameter may more easily accommodate a body within imaging device 20 and/or may provide greater field of view of the body using the above-mentioned detector and plurality of X-ray sources.
Telescopic arms 23 are coupled to gantry 12 and to housing 21. Telescopic arms 23 may be actuated in order to move housing 21 away from gantry 12 to a deployed position as illustrated in
Imaging device 20 is rotationally fixed with respect to treatment head 11 when in the deployed position. Specifically, imaging device 20 rotates along with treatment head 11 in response to any rotation of gantry 12. In some embodiments, the plurality of x-ray sources and the detector of imaging device 20 also remain fixed with respect to treatment head 11 before, during and after any rotation of gantry 12 while in the deployed position.
First plurality of X-ray sources 24 and second plurality of X-ray sources 25 are disposed farther away from gantry 12 than detectors 26 and 27. Accordingly, X-ray sources 24 and 25 may be pointed slightly back toward gantry 12 in order for their emitted beams to fall substantially squarely on respective detectors 26 and 27.
According to some embodiments, first plurality of X-ray sources 24 and second plurality of X-ray sources 25 are disposed along a 270 degree arc surrounding volume 55. Sources 24 and 25 may be evenly spaced along the arc and may be located within a plane perpendicular to axis 14. Sources 24 and 25 may exhibit any suitable spatial configuration that is or becomes known.
Detectors 26 and 27 may acquire image data based on received radiation in any manner that is or becomes known. For example, one or both of detectors 26 and 27 may comprise a scintillator layer and solid-state amorphous silicon photodiodes deployed in a two-dimensional array. In operation, the scintillator layer receives X-rays and generates light in proportion to the intensity of the received X-rays. The array of photodiodes receives the light and records the intensity of received light as stored electrical charge. The stored charge therefore comprises an acquired image that represents intensities at each location of a radiation field produced by a radiation beam.
Detectors 26 and 27 may comprise other types of imaging devices. For example, X-ray radiation may also be converted to and stored as electrical charge without use of a scintillator layer. In such imaging devices, X-rays are absorbed directly by an array of amorphous selenium photoconductors. The photoconductors convert the x-rays directly to stored electrical charge that comprises an acquired image of a radiation field. Detectors 26 and 27 may also comprise a CCD or tube-based camera. Such an imaging device may include a light-proof housing within which are disposed a scintillator, a mirror, and a camera.
The electrical charge acquired by detectors 26 and 27 represents attenuative properties of tissues through which the received radiation beams have passed. More specifically, each X-ray source of housing 21 creates a projection image by emitting a radiation beam toward its respective detector, and each projection image represents attenuative properties of tissues through which its respective beam has passed. Due to the arrangement of X-ray sources within housing 21, the projection images may overlap as illustrated in
Some embodiments of the foregoing features enable generation of a three-dimensional image based only on radiation beams emitted from sources 24 and 25 while in a substantially stationary position with respect to volume 55. In contrast, other systems require the rotation of X-ray sources around a target volume to successively acquire the projection images that are required to generate a three-dimensional image.
Input device 301 and output device 302 are coupled to processor 303 and storage 304. Processor 303 may execute program code to cause imaging device to perform any of the above-mentioned steps, and to generate three-dimensional images and slice images based on kilovoltage radiation beams received by a detector of device 20. The program code, three-dimensional images and slice images may be stored in storage 304.
Storage 304 may also store program code to generate and/or modify a treatment plan according to some embodiments. Such code may comprise the COHERENCE™ workspace or the KONRAD™ treatment planning system sold by Siemens Medical Solutions. Accordingly, storage 304 may also store radiation treatment plans in accordance with any currently- or hereafter-known format. The treatment plans may comprise scripts that are automatically executable by elements of room 1 to provide radiation therapy fractions. Each treatment plan may require a patient to be positioned in a particular manner with respect to treatment head 11.
Operator console 30 may be in a room other than treatment room 1, in order to protect its operator from radiation. For example, treatment room 1 may be heavily shielded, such as a concrete vault, to shield the operator from radiation generated by linac 10.
Each of the devices shown in
Initially, at 510, a housing including a plurality of X-ray sources and a detector is moved around a volume.
Telescopic arms 23 may move housing 21 from the parked position to the deployed position of
A respective kilovoltage radiation beam is emitted from each of the plurality of X-ray sources toward the volume at 520. In some embodiments, operator console 30 controls imaging device 20 to emit a kilovoltage radiation beam from each of radiation sources 24 and 25 toward target volume 55. Radiation sources 24 and 25 may be substantially stationary with respect to target volume 55 during 520. Consequently, a plurality of kilovoltage radiation beams is received at the detector at 530 after having passed through the volume.
A three-dimensional image is generated at 540 based only on the plurality of kilovoltage radiation beams received while the X-ray sources were substantially stationary. Detectors 26 and 27, for example, generate a projection image corresponding to each received radiation beam. Operator console 30 or any other element of treatment room 10 may apply currently- or hereafter-known computed tomography-based techniques to generate a three-dimensional image based on the projection images. As mentioned above, these techniques may take into account the different orbits around volume 55 within which X-ray sources 24 and 25 and detectors 26 and 27 reside.
At 550, it is determined whether the volume is properly positioned for radiation treatment. The determination at 550 may comprise comparing the generated three-dimensional image with an image provided by a pre-defined radiation treatment plan. In this regard, slice images generated from the three-dimensional image may be compared with slice images associated with the radiation treatment plan. According to some embodiments of 550, spatial coordinates of target volume 55 may be determined based on the generated three-dimensional image and compared with stored spatial coordinates.
The volume is repositioned at 560 if it is determined at 550 that the target volume is not properly positioned. The repositioning may be performed based on position error information output at 550. For example, the determination at 550 may comprise determining a specific translational and/or rotational spatial error (e.g., 4 mm X-axis, 0 mm Y-axis, −3 mm Z-axis) and the volume may be repositioned at 560 based on the determined error. Flow returns to 520 and proceeds as described above after 560.
Radiation is delivered according to a treatment plan at 570 if the determination at 550 is affirmative. More specifically, operator console 30 may control linac 10 at 570 to emit a megavoltage radiation beam toward target volume 55. The radiation beam may exhibit an energy, a shape, and a dose rate specified by a radiation treatment plan. According to some embodiments, 570 comprises rotating gantry 12 to various rotational positions and delivering a radiation beam to target volume 55 from each of the various positions. Imaging device 20 may be disposed in the deployed position or in the parked position at 570.
A housing including a plurality of X-ray sources and a detector is moved around a volume at 710. 710 may proceed as described above with respect to 510. In some embodiments, housing 21 is fixed in the position shown in
A megavoltage radiation is emitted from a treatment head toward a volume at 720. The volume is located at an isocenter of the treatment head. In the present example, treatment head emits a megavoltage radiation beam toward volume 55 under control of operator console 30. Operator console 30, in turn, controls linac 10 and the radiation beam parameters according to a radiation treatment plan.
In some embodiments of 720, the treatment head need not be positioned as illustrated in
Each of the plurality of X-ray sources of the housing emits a respective kilovoltage radiation beam toward the volume at 730 while the plurality of X-ray sources are substantially stationary with respect to the volume. As mentioned above, a plurality of kilovoltage radiation beams is received at the detector at 740 after having passed through the volume. Next, at 750, a three-dimensional image is generated based on the received plurality of kilovoltage radiation beams. Some embodiments of 730, 740 and 750 have been described herein and will not be repeated for the sake of brevity.
It is then determined whether the volume is properly positioned at 760. The determination at 760 may comprise, but is not limited to, any of the positioning determinations described herein. According to some embodiments, the treatment head may continue to emit the megavoltage radiation beam during 730, 740, 750 and 760. In such embodiments, it may be possible to efficiently facilitate radiation treatment monitoring.
Process 700 terminates after 760 if it is determined that the volume is not properly positioned. According to some embodiments, the volume may be repositioned as described above after 760 with radiation treatment resuming thereafter. Flow proceeds to 770 if it is determined that the volume is properly positioned.
Flow returns to 720 if it is determined at 770 that treatment is not complete. Flow therefore continues as described above through 720, 730, 740, 750 and 760 until treatment is complete. Imaging device 20 may be disposed in the deployed position or in the parked position during 720, 750, 760 and/or 770.
According to some embodiments, gantry 12 may be rotated and/or characteristics of the megavoltage radiation beam may be changed at any time during process 700. For example, treatment head 11 may be rotated around target volume 55 after 770 and prior to returning to 720. Process 700 may therefore be used to perform several radiation treatment fractions.
Those in the art will appreciate that various adaptations and modifications of the above-described embodiments can be configured without departing from the scope and spirit of the claims. Therefore, it is to be understood that the claims may be practiced other than as specifically described herein.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US6842502 *||Feb 16, 2001||Jan 11, 2005||Dilliam Beaumont Hospital||Cone beam computed tomography with a flat panel imager|
|US6888919||Nov 2, 2001||May 3, 2005||Varian Medical Systems, Inc.||Radiotherapy apparatus equipped with an articulable gantry for positioning an imaging unit|
|US7014361 *||May 11, 2005||Mar 21, 2006||Moshe Ein-Gal||Adaptive rotator for gantry|
|US7130372||Jun 8, 2004||Oct 31, 2006||Siemens Medical Solutions Usa, Inc.||Linear accelerator with X-ray imaging elements mounted on curved support|
|US7227925||Oct 2, 2002||Jun 5, 2007||Varian Medical Systems Technologies, Inc.||Gantry mounted stereoscopic imaging system|
|US20030048868||Aug 9, 2002||Mar 13, 2003||Bailey Eric M.||Combined radiation therapy and imaging system and method|
|US20050226364||Mar 31, 2004||Oct 13, 2005||General Electric Company||Rotational computed tomography system and method|
|US20070003004 *||Jun 30, 2005||Jan 4, 2007||Delgado Eladio C||Stationary computed tomography system and method|
|US20070133752||Dec 12, 2005||Jun 14, 2007||Moshe Ein-Gal||Imaging and treatment system|
|US20080212859 *||Aug 6, 2004||Sep 4, 2008||Da Silva Angela J||Calibration Image Alignment in a Pet-Ct System|
|1||PCT International Search Report dated Dec. 15, 2008 (International application No. PCT/US2008/008927).|
|2||PCT-Written Opinion of the International Searching Authority, Dec. 15, 2008, 6 pages (for International application No. PCT/US2008/008927).|
|3||PCT—Written Opinion of the International Searching Authority, Dec. 15, 2008, 6 pages (for International application No. PCT/US2008/008927).|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8494117 *||Oct 6, 2010||Jul 23, 2013||Siemens Aktiengesellschaft||Radiation therapy device|
|US8917813||Feb 23, 2011||Dec 23, 2014||Accuray Incorporated||Gantry image guided radiotherapy system and related treatment delivery methods|
|US8934605||Feb 23, 2011||Jan 13, 2015||Accuray Incorporated||Gantry image guided radiotherapy system and related treatment delivery methods|
|US20110085640 *||Apr 14, 2011||Franz Fadler||Radiation therapy device|
|US20120087464 *||Apr 12, 2012||Fmi Technologies, Inc.||Multi-source low dose x-ray ct imaging aparatus|
|U.S. Classification||378/65, 378/10, 378/9|
|Cooperative Classification||A61N2005/1061, A61B6/4488, A61B6/4028, A61B6/0457, A61N5/1049, A61B6/466, A61B6/4014, A61B6/032|
|European Classification||A61N5/10E1, A61B6/03B, A61B6/40B2, A61B6/46B10|
|Sep 17, 2007||AS||Assignment|
Owner name: SIEMENS MEDICAL SOLUTIONS USA, INC., PENNSYLVANIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JEFFERY, ANDREW;REEL/FRAME:019913/0387
Effective date: 20070824
|Sep 5, 2014||REMI||Maintenance fee reminder mailed|
|Jan 25, 2015||LAPS||Lapse for failure to pay maintenance fees|
|Jan 25, 2015||REIN||Reinstatement after maintenance fee payment confirmed|
|Mar 17, 2015||FP||Expired due to failure to pay maintenance fee|
Effective date: 20150125
|Apr 20, 2015||PRDP||Patent reinstated due to the acceptance of a late maintenance fee|
Effective date: 20150422
|Apr 22, 2015||FPAY||Fee payment|
Year of fee payment: 4
|Apr 22, 2015||SULP||Surcharge for late payment|